


Fate Moves at Light Speed

by Canislupus54



Category: Fate/stay night & Related Fandoms, Xenoblade Chronicles 2 (Video Game)
Genre: Action/Adventure, Crossover, Gen, Other
Language: English
Status: In-Progress
Published: 2019-03-05
Updated: 2019-04-29
Packaged: 2019-11-12 05:46:53
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 2
Words: 3,257
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/18004988
Author URL: https://archiveofourown.org/users/Canislupus54/pseuds/Canislupus54
Summary: Rather than Arturia Pendragon, Jin, the Paragon of Torna, is summoned to serve as Shirou Emiya's Servant Saber.





	1. Enter Saber

**Author's Note:**

> A note: Jin won't be able to use his full power whenever he wants. So he can't just stomp every Servant with light speed and absolute zero.

Shirou Emiya raised his head to look at his blue-clad assailant. All told, Shirou wasn't exactly having the best day of his life. He had a weird bruise on his hand, he got stuck cleaning the archery dojo until late at night, and when he finished to see two strange men fighting at superhuman speeds on school grounds, one of them chased him down and killed him.

Someone had healed Shirou, only for him to end up at the mercy of this strange man's spear once more.

"Not bad, kid," the spearman said. "That last move was pretty interesting." Using a magically enhanced poster as a shield was unorthodox. "You're quick on your feet but your magic could use work. Maybe you were meant to be the seventh. Well, either way, you're dead."

"No way," he said. "Someone healed me. I'm not going to die like this. I won't be killed by someone like you, who kills like it's nothing!"

A glow emanated from some abandoned corner of the storage shed the two had ended up in.

"The seventh Servant!?" the blue man exclaimed, just as a sword slammed into his hasty guard and sent him flying out of the shed.

A new man stood in the shed now. He had silver hair and wore a long white, armored coat a nodachi with a glowing red stone set in the hilt rested gently in his hands. His stance was relaxed, the sword held loosely at his side as he turned to regard Shirou.

"Are you my Master?" the silver-haired man asked in a quiet monotone. Shirou noted that his face was covered by a horned mask.

"Huh?" was Shirou's elegant response.

"Sit still. I'll handle this."

The swordsman strode out into the yard and stared impassively at the spearman.

"Nice of you to show up, Saber," the spearman said, grinning. "Not a bad entrance."

"I'm not here to talk," the now-identified Saber replied. "Let's finish this, Lancer."

Saber rushed forward in a blur Shirou could barely follow slashing upward at Lancer. Lancer managed to block the blow, but was launched into the air. Saber followed him, then slammed him down to earth with another strike. The blue man slammer into the ground, making a decent-sized crater.

Saber fell down, stabbing at Lancer, who leapt out of the crater and backward to avoid getting skewered.

Lancer charged. Shirou scowled. With Saber still recovering from that landing, Lancer had a good opening. Yet his spear thrust was easily deflected by Saber's sword. Saber followed up with another strike that sent Lancer sailing across the yard.

The spearman managed to land on his feet grinning.

"Let me ask you something before we continue, Saber," Lancer said. "Since this is our first meeting, would you like to call a draw?"

"No thanks," Saber replied. "I'll finish you here."

"Is that so?" Lancer asked, his sword starting to glow a bright red, overflowing with power.

A sense of dread overcame Shirou just from the spear's presence. The next blow would be fatal.

"Gae—"

Saber was behind Lancer, stabbing right at the man's heart. Lancer barely managed to twist his body so the blow missed anything vital. Saber withdrew his sword and frowned as Lancer collapsed to the ground, blood pooling around him.

"I see Lancer isn't called the most agile class for nothing," he said.

"What the hell was that!?" Lancer exclaimed. The man growled like a dog. "My Master's a coward, so he's ordering me to retreat. See ya around, Saber."

With that, Lancer leapt over the manor walls and out of sight.

Shirou, jaw agape, walked up to Saber. The silver-haired man turned to look at Shirou. The two engaged in an awkward staring contest for a moment, before Shirou collected himself and managed to speak.

"Thank you for saving me, but could you explain what just happened?" Shirou asked.

"I'm not entirely sure myself," Saber replied. "I remember dying, then I was here with all sorts of new knowledge in my mind. I do know that I'm your Servant, Saber, and I'm supposed to win some war for you. You're supposed to be supplying me with power as well, but that doesn't appear to be happening. I'll have to use my true strength sparingly."

"I see…"

"I'd rather not call you Master," Saber said. "Would you tell me your name."

"Um, Shirou Emiya."

"I see. You can call me Saber."

Saber turned his head toward the walls.

"More enemies are approaching," he said. "Stay here, Shirou. I'll deal with them."

His piece said, Saber leapt up over the walls around the Emiya household.

Shirou ran out the door after him to see Saber cutting down a man in a red coat-like garment. The other man had avoided the worst of the blow, but it was still a nasty wound.

"Archer!" a familiar female voice shouted.

"Wait, Saber!" Shirou shouted, his hand glowing briefly.

Saber stopped his attack and looked back at Shirou.

"What is it?" he asked. "I could have eliminated this enemy."

"I don't know what's going on!" Shirou shouted. "You keep talking about enemies and Servants but that doesn't mean anything to me! At least fill me in before you start slashing at people!"

"Is this really the time to discuss this?"

"I see," said the female voice again, drawing Shirou's attention to the girl standing behind the Archer. "So that's how it is, you novice Master?" the girl stepped forward, smiling and allowing Shirou to see her fully. Rin Tohsaka, a well-known schoolmate, stepped into the light. "Good evening, Emiya-kun."


	2. The First Battle Against the Strongest

**Summary for the Chapter:**

> Jin and Shirou learn about their situation and encounter Berserker for the first time.

**Notes for the Chapter:**

> Sorry for the long wait.

Jin sat in the _seiza_ position slightly behind Shirou, sizing up this girl, Rin Tohsaka for any signs of danger, while the two humans conversed about this Holy Grail War. Jin frowned. Slightly more than usual, anyway. Malos had once related the story of how the title of Aegis had come to be.

_“Indol had some ugly hunk of metal called the Aegis lying around, their most holy artifact. Looked more like a cup to me. I almost named myself the Holy Grail,” the male Aegis had said. “But I figured it would be better to just take the name that was already there.”_

Was there some connection between this Holy Grail War and the Aegis of his world? If so, what? The fact that the city outside resembled the Land of Morytha was also unnerving.

Tohsaka was explaining the basics of the war to Shirou. Jin hoped they made it quick. He hadn’t sat in this position since the fall of Torna, and it was one thing from the destroyed nation he didn’t miss.

He had only been paying partial attention, but he had already heard several unpleasant points. While his mind had been filled with knowledge of the War, it was jumbled, as if done in a rush. He couldn’t readily recall any facts about the War until they were immediately relevant. As such, much of what Tohsaka described was as new to him as it was to Shirou. The concept of Command Seals in particular grated on him. Three absolute orders that robbed a Servant of their free will? Disgusting. Thankfully, Shirou seemed unnerved by the idea as well.

After Shirou’s momentary shock at the concept of killing the other Master’s, the conversation turned back to Jin and he returned his full attention to it.

“Think of Saber like a familiar, granted to you to help you survive the Holy Grail War,” Tohsaka said.

Shirou threw a skeptical glance over his shoulder. “He doesn’t look like a familiar to me.”

“Well of course not,” Tohsaka said smugly. “Servant’s are technically familiars, but they’re really superhuman beings, heroes from the past.”

“Heroes from the past?”

“That’s right. Servant’s are pulled from legends, be they from the past or present, and given physical forms.”

“I was not,” Jin said in a level tone.

Rin turned toward him, eyes wide. She blinked slowly. “You weren’t what?”

“Summoned from the past or present. This world is unfamiliar to me.”

Another slow blink. “What!?” Tohsaka exclaimed.

Jin merely stared at her.

The girl cleared her throat and returned to addressing Shirou, as if her outburst had never happened.

“Well, that’s how it usually works. There are obviously exceptions to every rule.” She was trying to maintain her earlier smugness, but there was a clear shaking in her voice. “A-anyway, if you want to know more, you should talk to the man who oversees the war.”

“Wait,” Jin interjected. “From what I’ve gathered, Shirou should be supplying me with energy to maintain my physical form. That’s not happening. Would you know why that is?”

With a sigh, Tohsaka shook her head. “My only guess is that it’s because he’s an amateur and screwed something up. I couldn’t say what specifically went wrong.”

“I see.” Jin stood. “Well then, let’s go speak with this mediator.”

***

“I don’t trust that man remotely,” Jin said as the trio strode away from the church. Archer was also likely in the vicinity, but in that astral form.

“You shouldn’t,” Tohsaka said. “You’re a good judge of character, Saber.”

The priest was condescending and needlessly confrontational with Shirou.

Tohsaka abruptly stopped walking.

“We should part here,” she said. “Starting tomorrow, we’re enemies in a fight to the death. We shouldn’t get too close to each other.”

“I don’t really intend to fight you though, Tohsaka,” Shirou replied.

Tohsaka’s mouth hung agape for a moment. “Geez, why did I even bring you here? You don’t get it at all…”

A glowing mist seemed to swirl behind Tohsaka for a moment, before resolving itself into the form of Archer.

“Rin,” the other Servant said. “If an easily slain enemy presents itself, we should strike.”

Jin reached for the hilt of his sword.

Rin sighed. “I know that. But, well… I owe Emiya-kun. And I don’t think Saber will go down without a fight.”

Archer glanced at Jin. Their eyes met for just a second, but a clear scowl crossed Archer’s face, his eyes blazing with contempt. Did Archer know him from somewhere? Impossible. He clearly wasn’t in Alrest.

“You’re a good person, Tohsaka,” Shirou said with mood-breaking cheer. “I don’t dislike people like you.”

Archer huffed and began disappearing. “Call me when you’re ready to fight, then.”

Tohsaka was too busy blushing bright as a tomato to respond. So someone else did it for her.

“Hey, are you two done talking?” a high-pitched, childlike voice called out from behind Jin and Shirou.

Jin spun around to look at the source of the voice. A girl, perhaps around twelve years old, dressed in purple winter clothes, stood about thirty feet away. Her hair was snow white and her eyes crimson, an unusual coloration for a human.

More pressingly, a hulking, gray-skinned figure was materializing behind her, his red eyes devoid of thought or reason, filled with blind rage.

“Berserker?” Tohsaka muttered.

The girl walked a few feet forward into the light of a street lamp and curtsied.

“Nice to meet you, Rin,” she said. “I am Illya. Illyasviel von Einzbern. You know the name ‘Einzbern,’ don’t you?”

“I’m surprised,” Tohsaka said, her voice strained. “In terms of raw ability, that thing outclasses Saber in everything but Agility.”

There was a slight pause. Archer was probably saying something.

“So, it’s something we can’t beat with brute force, huh? Archer, use your class’s usual methods…There are three of us here, at the very least we can hold it off…Emiya-kun, it’s your decision if you want to run or fight, but try to run if you can.”

“Is your little conference done?” Berserker’s Master asked. “I’ll kill you now, then. Attack, Berserker.”

The lead skinned giant released a wordless, bestial roar before leaping an respectable height into the air and falling down toward Shirou, wielding his strange weapon that was some mix of a club, a sword, and an axe. Before anybody present could move, a barrage of glowing red arrows struck Berserker in the air and exploded in a dazzling light show, throwing Berserker off his path to land several peds away. More arrows flew through the air from a distant location, but Berserker deflected most of those with ease.

Standing in a crater without a scratch on him, Berserker gave a guttural growl before launching himself at Shirou at a truly impressive speed. Before he could even get halfway there, however, Jin was between them, striking at the beast’s heart. Berserker barely managed to deflect Jin’s much smaller weapon in time to avoid a fatal wound, then swiftly swung his club down with his full strength.

Jin parried the attack, a wave of air pressure emanating out from the attack and tearing apart the ground around the warriors.

A high-speed flurry of blows and parries followed, each exchange destroying the scenery more than the last. A nearby fence was essentially gone, the hill right next to the street was now more of a cliff. Berserker had no technique. Rather, he was simply able to attack quickly enough and with such ferocity that defending was difficult. He was also more than capable of parrying simple strikes.

A powerful overhead strike came down at Jin, the air screaming as it was displaced by the superhuman attack. Clashing blades was getting them nowhere. Another approach was needed. Jin sidestepped the attack, bracing himself for the blast of air that came as it hit the ground. Before the mad fighter could raise the weapon again, Jin firmly planted a foot on it, trapping it in the crevice its impact had made.

Berseker’s grip started to loosen. If he couldn’t fight with his weapon, he’d fight unarmed. Even in the grips of insanity, there was something to be said for the instincts and muscle memory of a seasoned warrior.

Unfortunately for Berserker, he was fighting someone with all that, and the capacity for coherent thought. A sheet of ice spread out from Jin’s foot, encasing the weapon and Berserker’s hand, preventing him from releasing the club.

An arc of silver flashed out as Jin’s sword sliced through the air, cutting through Berseker’s throat and sending a spray of blood in a semicircle on the surrounding area. Berseker’s head lolled backward, hanging only by the very back of his neck as the muscle-bound body slackened.

Jin stepped off the club and stepped back, eyeing the enemy for any surprises. He had fought enemies who self-destructed on death before.

“Saber!” Shirou called out as he ran toward the pair, evidently not sharing that experience.

“Shirou, stay back,” Jin said. “There might be a trap in the corpse.”

What actually happened, was far worse, however. Muscle and skin regrew as Berserker’s head reattached itself, shifting back into a more natural position as the flames of madness returned to the other Servant’s eyes.

Before the other Servant could go back on the offensive, Jin threw out a palm, causing numerous small icicles to materialize around him and fly at the giant, who deflected each with ease. More of Archer’s glowing red arrows bombarded the beast, to still no effect.

Still, it provided a momentary distraction. Jin rushed forward and slashed diagonally across the giant’s chest, his eyes widening in surprise at the resistance of its flesh. His sword cut far less deeply than it should, sparing Berserker from another death and leaving Jin overextended as the former prepared for another strike.

Jin moved back at light speed before the club smashed into the ground, sending up a cloud of smoke. He scowled. Was this thing adapting to the attacks that hit it? It wasn’t immune to his sword yet, but the effectiveness of the blade had been severely diminished. This was bad. The only other sure-kill ability he had was freezing this monster to absolute zero, and that would use up most of his energy. Combined with not knowing how many times Berserker could revive and the complete lack of effect Archer’s attacks had, and he had no idea if he even stood a chance of winning. Malos’ absolute destruction or Rex and Mythra’s ability to manifest their imaginations would have been very helpful right about now.

***

Archer gritted his teeth in frustration. What was this silver-haired pretty boy doing here? Where was _his_ Saber? This threw his plans completely out of balance, assuming they would even still work. He may well have been in an entirely different timeline.

First of all, he didn’t know the extent of this mystery man’s abilities, so he had no idea if Rin would be able to win with him like she could with Arturia.

Second, this fight with Berserker. Saber’s ungodly Agility and skill had allowed him to get in a quick kill, meaning the fight had never made it to the graveyard, or any isolated location for that matter. He couldn’t exactly fire anything big into the current battlefield. Disillusioned or not, he didn’t exactly want to kill anybody who happened to be in the blast range. Even putting that aside, the secret of the Holy Grail War and magic in general would be endangered, and he would definitely earn the suspicions of the other combatants, Rin included, if he attacked with anything stronger than what he’d already used.

Which meant he couldn’t kill Shirou or use anything powerful enough to harm Berserker. The fight seemed to have reached a stalemate. Berserker’s Noble Phantasm had allowed him to adapt to Saber’s sword and Saber had yet to use anything else that could harm the giant. Either he didn’t have anything like that, he was saving it as a trump card, or it was dangerous to use around allies. Only one of those was remotely comforting.

His arrows weren’t doing anything, but he’d catch hell from Rin if he just stopped firing, so there was nothing to do but attack.

***

It was a risky plan, but it would have to work. The giant adapted, but didn’t become immune to anything used against it, Jin observed as he landed a shallow cut on Berserker’s sword arm.

Once more accelerating into light speed, Jin appeared behind Berserker and thrust his sword with all his strength into the giant’s heart. It stopped just a few centimeters short. Just one more push and it would end. No time to waste, Berserker was turning.

With a shout of determination, Jin thrust the sword into Berseker’s heart, and froze it solid.

As the mad Servant’s body slackened once more, Jin withdrew his blade and returned to Shirou’s side.

“Shirou, we should go,” he said. He had used a fraction of his full power to freeze Berserker’s heart. If he had to use it, absolute zero should still be enough to kill Berserker again.

At least, that was the hope, seeing as Berserker was starting to move again.

“Your Saber is pretty interesting, Onii-chan,” Berserker’s Master suddenly chimed in. “I’ve never heard of a hero like him yet he’s already killed my Berserker twice. What kind of hero could go up against the greatest Greek hero like that?”

“What!?” Rin shouted. “You mean Berserker is…”

“That’s right, Heracles, the strongest Servant. Anyway, I get the feeling Saber is holding out on me, so I’ll let you live a little longer. Maybe he’ll show me what he can do next time. Let’s go home, Berserker.”

Remarkably, the seemingly mindless warrior turned calmly and followed his Master back down the street.

“That… was too crazy,” Rin muttered.

“So this is… the Holy Grail War…” Shirou said in awe.

**Notes for the Chapter:**

> I shortened or cut scenes that I felt wouldn't change enough to be worth narrating. I hope you enjoyed it, though.
> 
> Obligatory stats for Jin below
> 
> Servant Details
> 
> Class: Saber
> 
> Name: Jin
> 
> Titles: The Paragon of Torna. Leader of Torna
> 
> Abilities:
> 
> Strength: B
> 
> Endurance: C
> 
> Agility: EX
> 
> Magical Energy: C+
> 
> Luck: D
> 
> Class Skills:
> 
> Independent Action: A+
> 
> Magic Resistance: B
> 
> Presence Concealment: C
> 
> Personal Skills:
> 
> Eye of the Mind(True): A
> 
> Noble Phantasms:
> 
> Blade (The Gift of God): Saber's nature as a being. A power that is intrinsic to what he is and thus is active at all time. This grants Saber access to all abilities he had as a Blade in Alrest.
> 
> Flesh Eater (Lora's Heart): The power gained by Saber through devouring his Driver's heart. Like Blade, this is an inherent part of Saber and thus he has access to its power at all times, including control of elementary particles, allowing him to move at light speed or freeze objects or entire areas to absolute zero.


End file.
